Bracing and spacing device for concrete wall forms



De@ 10, 1958 HANS-DIETER KLAlss 3,415,484

BRACING AND SPACING DEVICE FOR CONCRETE WALL FORMS Filed Aug. 27, 1965FIGI 2 Sheets-Sheet 1 l INVENTOR HANS- DIETER KLAISS ATTORNEYS Dec. 10,1968 HANS-D|ETER KLAlss 3,415,484

BRACING AND SPACING DEVICE FOR CONCRETE WALL FORMS Filed Aug. 2T, 1965 2Sheets-Sheet 2 FIGB h u i a* -|o 5 al, V

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A M IO 34 35 2 33 H0142 2 A A ,lll/lili.. lll/[fil 2 INVENTORHANS-DIETER KLAISS BY @4cm/6% ATTORNEYS United States Patent O 3,415,484BRACING AND SPACING DEVICE FOR CONCRETE WALL FORMS Hans-Dieter Klass,Stuttgart, Germany, assignor to Dynamit Nobel Aktiengesellschaft,Troisdorf, Germany Filed Aug. 27, 1965, Ser. No. 483,137 Claimspriority, application Germany, Aug. 28, 1964, K 53,873 14 Claims. (Cl.249-216) ABSTRACT OF THE DISCLOSURE A bracing and spacing device forconcrete wall forms to be inserted between oppositely positioned formsat spaced intervals to brace and accurately space the forms. A pair ofhead members are secured to the inner face of each of the oppositeforms, respectively, by means of bolts inserted through the form fromthe outer side and screwed into outwardly opening blind end centrallylocated bores in the head members. Two parallel rod braces extendbetween the head members on diametrically opposite sides of therespective boll'ts. The head members are constructed of plastic moldedabout the rods, which are deformed at their ends for tight securement.

Background of the invention In spite of the general simplicity ofconstruction of concrete forms there are several considerations whichhave provided diiculties in the past in connection with suchconstructions. One of these considerations is the proper spacing andbracing of parallel forms over their entire surface so as to achieve aconcrete end product, such as a wall or the like, having truly parallelsurfaces. In attempting lto solve this problem, ithas been proposed thatthe concrete forms beconstructed with the use of securing devicespositioned at prescribed intervals throughout the form, which devicesserve as braces for the form walls against the forces `created by thewet concrete and also serve to accurately position the form walls so asto insure a parallel disposition thereof.

In connection with this type of bracing and spacing devices, oneconstruction is known in the art which consists of a single, rod-shapedbrace for bracing and determining `the distance between the forms andwherein the planking boards rest against both ends of annularintermediate members secured to the free ends of this support. There isalso provided in this known construction in both ends of this singlebrace, bores with an internal thread into which the clamping bolts,which extend through the plankings or forms, engage to secure the braceto the forms and to provide a support therefor. This axially symmetricalconfiguration of the device is unfavorable, however, by reason of thefact that the entire support assembly due to its axially symmetricalconfiguration will very easily turn with the clamping bolts when theclamping bolts are withdrawn even after the concrete has set. As aresult, an interspace having an annular cross section will be formedbetween the support and the hardened concrete; into which interspacewater can easily seep and possibly penetrate also through the concrete.Even if the conical openings remaining after the removal of theintermediate members are closed off by means of plugs or the like, theproblem of Water seepage remains as serious consideration.

In another known construction of such a device, two rod-shaped bracesextending parallel to each other are provided at both ends thereof withaxiallly symmetrical head pieces adapted to be secured to the plankingsof the concrete form for spacing and bracing thereof. In this instance,helical wires are disposed between the adjacent 3,415,484 Patented Dec.10, 1968 ICC ends of the pair of braces, which wires connect the twosupports with one another and constitutes simultaneously an internalthread for the shafts of the clamping bolts, which extend through theplanks to secure the form to the support member. While these two bracestogether with the helically provided wires connecting the former withone another constitute an asymmetrical structural part, which istherefore torsion-resistant, the danger exists with this constructionthat, after the removal of the axiallly symmetrical head pieces, waterwill seep through the remaining openings, which must again be closed offby plugs or the like, into the cavity surrounded by the helical wires,and, in case the hardening concrete present between the two cavities isnot completely set, water will penetrate through it. Additionally, thereexists the danger that the two braces will corrode or rust through sothat after a time the water can possibly penetrate through the concretealso along `these supports.

Summary of the invention The present invention is directed to such abracing or spacing device which is suitable for securing the plankingsor forms used in the construction of concrete walls, and consistsbasically of at least two rod-like braces of selectively predeterminedlength supported in parallel relation to one another by a pair of headpieces secured to opposite ends thereof. The head pieces accuratelyspaced by the rod-like braces are then removably secured to oppositelydisposed planks or forms by means of clamping bolts extending throughthe plankings or forms from the outside thereby simultaneously bracingand accurately spacing these forms.

rPhe present invention has the object of providing a bracing and spacingdevice in which the penetration and also the permeation of water throughthe concrete is with certainty prevented in every case.

It is a further object of the present invention to provide a bracing andspacing device which is simple and economical in manufacture so as topermit a retaining of the entire device in the hardened concrete withoutgreat expense.

It is another object of the instant invention to provide a bracing andspacing device which may be easily adapted to any length and easily andfirmly secured to the opposing walls of the concrete form.

It is still a further object of the instant invention to provide abracing and spacing device which is so constructed as to be visible inthe surface of the concrete to as little an extent as possible.

It is still another object of the instant invention to provide a bracingand spacing device which is constructed so as to make possible a simpleremoval of any portion visible in the surface of the concrete.

In order to achieve these objects it is proposed, in accordance with thepresent invention, that the head pieces be provided of non-symmetricalconfiguration in that in each head piece the bore for receiving theclamping bolt shafts is provided as a blind-end bore formedconcentrically in the head piece and the recesses for receiving the endsof the rod-shaped braces are provided in projections disposedeccentrically on the head piece. By virtue of this particularconfiguration, not only the two-rod shaped braces but also the two headpieces connecting the braces with one another are positioned in thehardened concrete in a torsion-resistant manner so that they too will beseated tightly, sealingly in the concrete and cannot become loose evenwhen the clamping bolts are withdrawn. Since, additionally, the boresserving for receiving the clamping bolt shafts are constituted asblindend bores, in a head piece made of waterproof synthetic or plasticmaterial, no water can seep through these bores into the concrete and nocorrosion of the head piece forming a passage for water can occur. As aresult thereof, there is also no need to specifically close off theremaining openings of the blind-end bores with plugs or the like, whichhas, in turn, a favorable effect particularly with regard toconstruction cost and cost of materials. Finally, this tension and.'compression resistant device may also be adapted to a limited extent tothe respectively prevailing conditions inasmuch as Ithe total length ofthe device may be shortened by twisting or also by racking or bendingthe braces toward each other.

If the aforementioned head pieces or members are made from syntheticmaterial, these head pieces may be formed around the deformed ends ofthe braces which will not only considerably simplify the manufacture ofthe device, but will additionally protect or shield braces made frommetal against any water which could possibly enter the apertures in thehead members provided for such braces from the outside, and thuseliminate a priori any corrosion thereof. In addition, the manufactureof the head members from synthetic materials will make it possible toretain the entire device in the hardened concrete without great expense.

In order to insure a good support of the deformed ends of the braces inthe synthetic material, it is advantageous to provide these ends with areduced portion having an out-of-round, rectangular, triangular, orrhombic cross section. For purposes of being enlarged with respect tothe synthetic material surrounding them, the ends of the braces may beprovided with rib portions, indentations or the like extendingtransversely and diagonally to the longitudinal axis of the brace, and,in that case, the transverse rib portions may be disposed on one sideand the diagonally-extending rib portions may be arranged on the otherside. In case the diagonally-extending rib portions are inclined andprovided in such a manner that they constitute in each case thecontinuation of the transverse rib portions disposed at the other side,this will practically have the effect `of a continuous rib portionfollowing approximately the line of a screw thread.

In order to facilitate the insertion of the clamping bolts into the headmembers, each of the blind-end bores provided in the head members isprovided with an opening which widens outwardly in the form of a cone inwhich case the end face of the head member surrounding the aperture ofthe blind-end bore may be constituted as an annular surface. On the onehand, this annular surface of the head members assures a sufficientlylarge bearing surface for the plankings or forms, and on the other hand,it is sufficiently small to be apparent in visible surfaces of theconcrete only to a very minor extent, Moreover, this annular surface maybe plastered with concrete without specific expenditure and thus readilycovered, if such is desired. In addition, if it should prove to benecessary, the openings of the blind-end bores may, of course,additionally be closed off by means of plugs or also with concrete.

Furthermore, rib portions may also be disposed within the area of theeccentric parts of the head member and additionally effect -a specialanchorage of the head members in the concrete. If, in this case, the endfaces of these rib portions terminate ush with the annular end face ofthe head member, the entire bearing surface for the plankings or formsmay be increased thereby.

Likewise, it -is of advantage, particularly in the case where thesupport members extend to visible surfaces of the concrete, to providethe rib portions cross-wise so that they will extend suitably to thearea of the internal thread of the blind-end bore and support theconcrete introduced between the rib portions, while thus preventing anybreaking-out of concrete when the clamping bolts are withdrawn.

Furthermore, specifically in the case where the support members extendto visible surfaces of the concrete, it is also possible to provide, ifdesired, a collar portion surrounding the aperture of the blind-end borewhich will be CII pressed into the planking or form and thus prevent anyoutflow of concrete through the hole in the form which accommodates theclamping bolt for the head members. In order to absorb the compressivestresses arising when the planking or form is braced by these devices ofthe invention, and in order to thus prevent the head member from beingpressed thereinto, the contacting or bearing part containing the annularsurface is preferably provided as an annular disc which is connectedwith the head member by means of deformable supports or the likearranged at the periphery therof which will be deformed by thecompressive stresses applied by the clamping bolt to the head memberthereby preventing the latter from being pressed into the form. For thesame purpose, it is also possible that the bearing or contacting partwhich is provided as an annular disc may be supported on the head memberby means of a projecting collar portion surrounding the aperture of theblind-end bore, which collar is also deformable to prevent the headmember from being pressed into the form. Finally, the discshapedcontacting part may, in this case, additionally also be subdivided intoat least two annular sectors which are connected, by means of bracketsor supports extending preferably outside of the head member.

Furthermore, during the assembly of the device and when screwing in thesecond clamping bolt in order to prevent the device as well as the firstclamping bolt from rotating at the same time, it is advantageous thatthe bearing or contacting surfaces of the clamping bolt heads facing theplanking or form have either projections or arched-out portions, andthat the supporting discs through which extend the clamping bolts havecurvatures, rib portions, or the like which project against the clampingbolt heads and which engage, in turn, between the projections or thearched-out portions of the clamping bolt heads, thus effecting thedesired sability against rotation.

Brief description of the drawing Several embodiments of the bracing andspacing device proposed by the present invention, as well as detailsthereof, are illustrated, by way of example, in the attached drawings,wherein:

FIGURE l illustrates the device according to the present invention inits operative position in sectional view;

FIGURE 2 shows the right-hand part of the device illustrated in FIGURE 1in a longitudinal cross-sectional view;

FIGURE 3 is a lateral View of the head member;

FIGURE 4 is a top plan view of the head member;

FIGURE 5 is a front elevational view of the head member;

FIGURES 6 and 7 show specific designs of the heads of the clamping boltsas well as of the coordinated supporting discs;

FIGURES 8 through 1l show specific designs of the head members; and

FIGURES 12 to 16 show in cross section deformations of the brace ends inaccordance with the invention.

Description of the drawing The clamping and expanding device illustratedin sectional view in FIGURE 1 comprises two rod-shaped metal braces 1extending parallel with respect to each other. The suitably deformed orat least roughened ends 2 of these braces 1 are inserted in pairs intohead members 3 made from synthetic material, which members 3 connect thebraces 1 with another. The head members are provided with annularbearing surfaces 4 which contact the planking or form boards 5 therebybracing and accurately spacing these forms at a distance D from eachother.

In order to be able to press these planking boards S, for example bymeans of spacing members, which may take the form of square timbersdesignated with reference numerals 6 and 7, against the end faces 4 ofthe head members 3, thus securing them in position, clamping bolts 8 areprovided which extend through interspaces 9, provided between the squaretimbers 6 and 7, and through bores 10 in the planking boards 5 and arescrewed with the threaded shaft or shank 11 thereof into the internalthread 12 of a concentric blind-end bore 13 disposed in thecorresponding head member 3. For the purpose of facilitating thisinsertion or introduction of the clamping bolts 8 into the blind-endbore 13, the opening 14 of this blind-end bore 13 widens conically inthe manner illustrated in FIGURES 3 and 5. Finally, a supporting disc,identified with reference numeral 15, is positioned against the spacingmembers 6 and 7 and engages with the head 16 of the bolt 8 therebyenlarging the bearing surface of the head 16 of the clamping bolts 18 onthe spacing members.

As is further apparent from FIGS. 3 to 5, the annular portion 17 of thehead member 3 is provided concentrically with the blind-end bore 13whereas the two projections 18 of the head member 3, serving forreceiving the brace ends 2, will assume an eccentric position and areslightly set back with respect to portion 17. Due to this particulardesign and configuration of the head members 3, the latter constitute astructural element which is outof-round. As a result, after the concretehas been poured between the planking boards 5 and has hardened, thishead member is securely seated in the concrete and can no longer becometwisted even when the clamping bolts 8 are withdrawn. Both areinforcement of the head member 3 and a guarantee against the torsionaldisplacement thereof may additionally be attained by the provision ofrib portions, designated by reference numeral 19, which are disposed ineach case within the area of the projections 18. The end faces 20 ofthese rib portions 19 projecting beyond the eccentric projection 18terminate flush with the annular end face 4 of the annular portion 17surrounding the blind-end bore 13 and thus constitute an enlargedbearing surface for the planking boards 5.

In the illustrated embodiment of the head members 3, which isparticularly suitable for visible surfaces of the concrete, theconcentric structural part 17 also projects forwardly only to the extentof the eccentric projections 18 in the manner as seen in dashed lines inFIGURES 3 and 4. In this case, the rib portions 19 projecting over bothstructural elements 17 and 18 are provided crosswise and constitutecross-shaped bearing surfaces, as has been illustrated in FIGURE 5. Theinner rib portions 21 will then protrude into the plane of the internalthread 12 and a thread identical to the internal thread 12 is then cutinto the rigdes 22 thereof facing the threaded shaft 11. Due to thisconstruction, the concrete introduced into the form will settle betweenthe individual rib portions 19, and the rib portions 21 will support theset or hardened concrete and prevent the concrete in this area frombreaking out when the clamping bolts 8 are removed from the headmembers.

The manipulation or operation of the device according to the presentinvention is extremely simple: When one of the planking or form wallshas been erected, the clamping bolts 8 coordinated to this wall areinserted through the bores 10 provided in the planking boards 5 andscrewed into the head member 3 facing the same thereby securing the headmember 3 firmly to the wall. Thereafter, the other planking or form wallis erected and the head member is secured to this wall by means of itsclamping bolt 8. The braces 1 are then inserted in the aperturesprovided in the head members 3. By means of a simple tightening of theclamping bolts 8 on both sides of the form the planking or form may berigidly clamped, which assures that the inside distance, in other words,the inside width D between the planking boards 5 is constant over theentire form. After the removal of the clamping bolts 8 as well as of theplanking boards 5, after the concrete has set, the entire device remainsin the hardened concrete, and the braces 1 and head members 3 arecompletely covered by the concrete except for the end faces 4 and 20 andthe orices 14 thereof.

In order to prevent the device and the first clamping bolts 8 fromrotating when the second clamping bolt 8 is screwed in or tightened,projections or teeth designated by reference numeral 24 are disposed, ina manner shown in FIGURE 6, at the bearing surfaces 23 of the clampingbolt heads 16 facing the supporting discs 15 and thus project againstthe supporting discs 15 during securing of the bolt and come to restagainst one or more project- ,ing ange or stop members 25 on thesupporting discs 15, thereby preventing any further rotation of theclamping bolt 8. Instead of the projections 24 it is also possible toprovide the bearing surfaces 23 of the clamping bolt heads 16 facing thesupporting discs 15 with a recess or recesses 26 corresponding in shapeto the stop member 25 of the supporting discs 15 into which thereinforcement 25 meshes in the manner illustrated in FIGURE 7, thussecuring the clamping bolt head 16 against a displacement or furtherrotation thereof.

In order to conceal the head member 3 in the concrete as much aspossible, it is advisable to tighten the clamping bolts 8 only lightly,or to loosen the same again to some degree after tightening thereof.Since the planking boards 5 will be pressed outwardly to some extent dueto the weight of the concrete, any outflow of the concrete through thebores 10 provided in the planking boards 5 must be prevented in order toobtain a smooth concrete surface. For this purpose, the provision anddesign of the head member 3, according to FIGURE 8, proposes that at theannular bearing surface 4 thereof a projecting collar 27 be disposedwhich surrounds the orifice 14 of the blind-end bore 13 and engages bymeans of the pointed end rim 28 thereof with the planking board 5 towhich it is secured, thereby guaranteeing a faultless closure. If thebearing surface 4 of the head member 3 is additionally curved away fromthe planar surface of the planking board 5 in a arcuate manner, theconcrete may penetrate also between the planking board 5 and the bearingsurface 4 of the head member 3 so that the essential end face of thehead member 3 is also covered with concrete and thus will no longer bevisible.

FIGURES 9 through 11 illustrate advantageous structural designs of thehead member 3 in order to prevent a penetration thereof into theplanking lboard 5, which would result in an undesirable projecting ofthe head member from the finished concrete surface. For this purpose,the head member 3, illustrated in FIGURE 9, comprises a separate fittingor bearing part provided as an annular disc 29 which is connected to thehead member 3 by means of a plurality of deformable brackets 31 disposedalong the outer periphery 30 thereof. If, in this embodiment of the headmember 3, the respectively coordinated clamping bolt 8 is tightened totoo great an extent, the resultant pressure will be absorbed by virtueof the deformation of the bracket 31 and any penetration of the annulardisc 29 into the planking board 5 is thereby prevented.

In the embodiment shown in FIGURE 10, the annular disc 29 is supportedby means of a collar 32 which surrounds the orifice 14 of the blind-endbore 13, and is subjected to the deformation and absorbs excessiveforces applied by the clamping bolts in a manner similar to brackets 31in FIGURE 9. This collar 32, which may also be provided with recesses tomake it more easily deformable, if desired, has additionally such aweakening effect that the annular disc 29 may be broken out of theconcrete after the same has set. If the thus resulting recess is lledwith fresh mortar, the head member 3 remaining in the concrete will becompletely invisible.

With respect to the embodiment of FIGURE 11, two half discs 33, forexample, of semi-circular configuration enclose the clamping bolt 8 andare connected with the jacket 34 of the head member 3 by way of brackets35. At the time the clamping bolts 8 are tightened, the pres- 7 surewill be applied from the planks to the half discs 33 so as to bend thebrackets 35 until they break olf, which in turn, will result in theremoval of the half disc 33. Accordingly, the head members 3 will beinvisible in the face of the concrete in this case also.

FIGURES 12-16 illustrate the possibility of achieving, by a deformationof the ends 2 of the braces 1, a highly secure anchoring of the bracesin the plastic head members 3 and therewith also a good transmission ofthe tractive forces between these members. As is apparent from FIGURES14-16, the bracket ends 2 may be deformed, as by being squeezed olf orpressed in such a manner that the cross section thereof may obtain aneither triangular, rectangular or also rhombic configuration.

Additionally, and according to FIGURES 12 and 13, rib portionsdesignated by reference numerals 36 and 37 may be formed into the braceends 2. The rib portions 36 are formed at the upper side extendtransversely to the longitudinal axis of the bracket ends 2, whereas therib portions 37 formed at the underside are, instead, inclined withrespect to the axis of the brackets. The inclination of these ribportions 37 may, in that case, be so chosen that these rib portions 37will be provided immediately adjacent the transverse rib portions 36 sothat practically a continuous rib 36-37 will be formed followingapproximately a screw line.

Thus, while I have shown and described several embodiments in accordancewith the present invention, it is obvious that the same is not limitedthereto, but is susceptible to numerous changes and modifications asknown to a person skilled in the art, and I therefore do not wish to belimited to the details shown and described herein, but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

I claim:

1. A bracing and spacing device for concrete wall forms of the typewhich is inserted between oppositely positioned forms at spacedintervals so as to brace and accurately space said forms comprising apair of noncorrosive head members each capable of being secured to theinner face of a form by means of a 4fastening member inserted throughsaid form from the outer face thereof, and

at least two elongated brace members having their respective endssecured to said pair of head members so as to extend substantiallyparallel to one another.

said head members being axially non-symmetrical so as to be incapable ofrotation when imbedded in substantially solid concrete,

said head members being provided with bore means in the form of ablind-end bore for lockingly receiving said fastening member.

2. A bracing and spacing device for concrete wall forms according toclaim 1, projections including blindend recesses opening oppositely tosaid blind-end bore disposed eccentrically on said head members forreceiving fand securing the ends of said brace members in said headmembers, said blind-end bore being disposed concentrically in said headmembers.

3. A bracing and spacing device for concrete wall forms according toclaim 2, said head member being made of synthetic material.

4. A bracing and spacing ldevice for concrete wall forms according toclaim 2, the ends of each of said brace members being deformed so as tosecurely engage with said head members.

5. A lbracing and spacing device for concrete wall forms according toclaim 4, the ends of said brace members being squeezed oif so as to havea cross section of regular geometric non-circular configuration.

6. A bracing and spacing device for concrete wall forms according toclaim 5, the outer ends of said brace members being provided with ribportions extending transversely to the longitudinal axis of saidmembers.

7. A bracing and spacing device for concrete wall forms according toclaim 2, said blind-end bore being widened concially outwardly at theopening thereof, the end face of each said head member surrounding theopening of said blind-end bore being provided as an annular surface.

8. A bracing and spacing device for concrete wall forms according toclaim 2, support ribs positioned on said head members in the area ofsaid projections for increasing the area of the end face thereof.

9. A bracing and spacing device for concrete wall forms according toclaim 7, said annular surface of said head members being arcuate incross section so as to slope away from the center.

10. A bracing and spacing device for concrete wall forms according toclaim 9, a projecting collar provided in said annular surface formingthe opening for said blind-end bore.

11. A bracing and spacing device for concrete wall forms according toclaim 7, said annular surface forming part of an annular disc, saidannular disc being connected to the remainder of said head rmember bymeans of deformable support means, collapsible in response to axialpressure on said annular disc.

12. A bracing and spacing `device for concrete wall forms according toclaim 11, said annular surface of said head members being arcuate incross section so as to slope away from the center.

13. A bracing and spacing device for concrete wall forms according toclaim 11, said deformable support means being provided as a collarintegral with said annular disc and forming an enlarged portion of saidblind-end bore.

14. A bracing and spacing device for concrete wall forms according toclaim 2, said fastening members being in the form of threaded clampingbolts having a head portion, supporting disc means engaging with thehead portion of said clamping bolt for increasing the bearing surfacethereof, and stop means on said head portion and said supporting discmeans for preventing relative rotation thereof, said stop means being inthe form of at least one projection on the periphery of said headportion and an arched portion on said supporting disc means in line withthe periphery of said portion, and a recess in said head 'portion havinga shape corresponding to said arched portion.

References Cited UNITED STATES PATENTS 1,667,253 4/ 1928 Hawley 249-40 X1,735,017 11/1929 Smith 249-216 1,808,912 6/1931 Willard 249-46 X1,950,018 3/1934 Anderson 249-215 2,029,147 1 /1936 Anderson 249-2172,235,442 3/ 1941 Parmenter 249-217 2,292,548 8/ 1942 Schenk 249-216 X2,335,338 11/1943 Hillberg 249-215 2,728,127 12/ 1955 Armstrong 249-217X 3,199,827 8/ 1965 Terry 249-216 X FOREIGN PATENTS 491,003 1/1919France.

174,458 2/1922 Great Britain.

213,079 7/ 1956 Australia.

927,647 5/ 1963 Great Britain. 1,352,467 1/1964 France.

WILLIAM I. STEPHENSON, Primary Examiner.

U.S. Cl. X.R.

